Nope. Something interesting though - I just made a copy of your template and opened it and tried to print. The message box appeared again, so that excited me, and it printed with the underscores in place of the placeholder text as it should. Yay!... then I tried it again and it's back to not working
So something is clearly happening that I can't explain and I'm sure it's almost impossible for you to figure out without access to my computer. I don't understand what could possibly be happening though and it's very frustrating.
I'm open to any more suggestions but I suppose I'll just move on and forget about implementing this into my document.